Crocodiles

About Crocodiles[]

The Crocodile has always figured prominently in tropical Australia. The crocodile is a prominent figure in aboriginal culture, appearing frequently in stories, songs, artwork and other parts of the culture of tribes in the region.

The croc has also emerged as a symbol of the region. The Townsvile Crocs are one of the region's pro basketball teams. There are car rental companies, hotels, restaraunts, even an ice cream bar named after crocodiles. The toothy grins of these cartoon figures appear all over the place.

About Freshwater Crocodiles[]

Australia hosts two different species of crocodiles, both of which are native to Tropical Queensland.

The freshwater crocodile (also called Johnstone’s Crocodile) is found in inland freshwater areas of the Australian tropics and occasionally in the tidal portions of rivers. They are only found in Australia. Their range does overlap with saltwater crocodiles, and they can be found in the same locality.

Male freshwater crocodiles grow up to 3 meters in length, although females are much smaller, rarely growing longer than 2 meters. Both species mature at around 15 years of age.

The diet of freshwater crocodiles includes all the smaller animals you find near in and rivers; insects, fish, frogs, turtles, waterbirds and snakes are the most common diet items. Small mammals that come to drink at rivers are also sometimes taken. Even the larger adults feed mainly on these smaller prey.

One item not on freshwater crocodile diet list is people. According to the Queensland Parks and Widlife Service they are “…usually inoffensive, but will bit if provoked.” “…there is no record of an unprovoked attack on any person by a freshwater crocodile.” We have had old timers tell us of having swum with freshwater crocs back at the bush swimming hole when they were kids, but we would urge you use caution, even if you think you can tell which species is which.

“Freshies” breed during the tropical dry season, during the months of July and August. Females will dig a hole in a sandy riverbank, and lay up to a dozen eggs. The eggs will hatch in two to three months. The timing of hatching is near the start of the wet season when food for the young (mostly insects) is particularly abundant. The gender of the young is determined by the incubation temperature, extremely high or low incubation temperature produce females, mid-range temperatures produce males.

About Saltwater Crocodiles[]

salwater aka estuarine crocodile[]

The saltwater, or estuarine crocodile is found in estuaries, rivers, lagoons and swamps of the Australian tropics, from along the east coast south of Mackay all the up the coast to Cape York, and across the coastline of the northern half of Australia. Saltwater crocs are also found off beaches, and even a considerable distance up rivers and creeks in this region. Last year, beachgoers in Palm Cove stayed out of the water for a few days when a saltwater croc was spotted off the beach. Parts of their range do overlap with freshwater crocodiles, and they sometimes can be found in the same locality.

Saltwater crocs can grow to a very large size. While females can grow up to 4 meters in length, males can reach 7 meters in length and weigh over 1,000kg. No one is certain how long saltwater crocs can live, the only age records are from zoos and crocodile farms which have kept individuals captured as adults for over 50 years.

As adults of this species grow larger than freshwater crocodiles, they are capable of eating very large prey. Large crocodiles can ambush and kill cattle and horses as they come to drink at waterholes. Prey can also include wallabies, pigs, and even other crocodiles.

Humans are in the size range of the prey of saltwater crocodiles 3m and over, and attacks on humans occur ever year. The incidence of attacks on people is not high and in most cases the persons involved were not following the “be croc-wise” recommendations of the Queensland Parks and Wildlife Service. Visitors to the area from overseas, who may not be live in an area where large predators are present need to follow these guidelines and to be active in reducing the risks when they travel in croc country.

Saltwater crocs breed during the wet season (November-March). Males maintain large territories, even swimming in the ocean between river systems to increase their chances of breeding with adult females. Females will lay build a nest: a large pile of vegetation, sand and soil, usually located along the banks of a river, swamp or estuary. She will lay up to 50 eggs in the nest.

Females will lurk nearby the nest during the three-month incubation period, and can be quite defensive (don’t hang around crocodile nests!). The mother will sometime help dig out the hatching young, even carrying them down to the relative safety of the water. She will hang out near the hatchlings and protect the young, which make a squeaky sound when they are alarmed. Like with freshwater crocs and sea turtles, incubation temperatures in the next will determine the gender of the offspring. Crocodile farms use this fact to influence the gender of their hatchlings, producing more males, since they grow to marketable size faster.

How to tell freshwater from saltwater crocodiles[]

There are many subtle differences between saltwater and freshwater crocodiles, which we won’t mention here. (Who wants to get that close to a crocodile to figure out what species it is.)

Crocodylus-johnstoni-2 — *Freshwater Crocodile*

The most easily noticed difference between the species (besides size) is the shape of the head and teeth.

Freshwater crocodiles have longer and thinner snouts, with a straight jawline, and all their teeth nearly equal in size.

Saltwater crocodiles have a broad, powerful-looking snout, with an uneven jawline. Their teeth vary in size with some almost twice the size of others. (We do not recommend getting close enough to look at their teeth.)

Crocodile Conservation[]

These two species of crocodiles, being the largest predators in their homes, are no doubt important to the balance of the ecosystem. Not only does their predation effect other species, but birds, snakes, and fish eat crocodile hatchlings. Because of the important status and uniqueness crocodiles are protected species in Australia, and it is illegal to harm or kill either species.

This was not always the case, as up until 1972 crocodiles were hunted, for their skins, which were made into leather goods of all kinds. Populations at that point were highly reduced by hunting, but since then populations of both species have rebounded. You still meet older men in town who at one time of their lives supported their families by hunting crocodiles.

The future of the freshwater crocodile seems pretty secure, even though the species is only found in Australia, its populations are stable or growing. Populations of saltwater crocodiles in other countries, such as New Guinea and Indonesia, are still dropping, as hunting still continues in some countries outside Australia.

Within Australia the prospects for saltwater crocodiles seem good in some areas, but is uncertain in others. The remote regions of it’s range will likely remain remote for the foreseeable future, they can live and breed largely undisturbed there.

Along the populated eastern coast of Australia, the presence of these predators creates a conflict between conservation and public safety, and issue that will remain unsettled for some time. Along parts of the east coast, crocodile populations of crocodiles have not grown since their protection began. As human populations grow, the potential for problems may increase. Habitat loss could reduce the crocodile populations further.

Crocodile populations in populated areas are monitored and managed. In between the Daintree River and Cairns, all crocodiles found are captured and relocated to crocodile farms. While this protects the human population in this area (many of whom are visitors and not as familiar with being “croc-wise”.) it concerns some environmentalists, who point out that the rivers in this area are missing their most important predator, which may effect the ecological health of the river. They also point out that because saltwater crocodiles are migratory, these rivers cannot be assumed to be croc free, as a croc could have moved in recently.

Others point out that by minimizing the chances of problem encounters between people and crocodiles, and by educating the public on how to live safely alongside crocodiles, public opinion may evolve further towards complete support of conserving crocodile populations, even in areas close to human population centers. It will be interesting to see what happens to these eastern coastal populations of crocodiles in the coming years.

Important note[]

what ever the species, whether croc or gator, fresh or salt, big or small, do not play with them!

Safety tips[]

Don’t swim where crocodiles live.
Fish a few meters back from the edge of the water. Don’t stand on logs or branches over deep water. Crocodiles are ambush hunters, and able to lunge out of the water.
Avoid activities near the water’s edge or on sloping banks. Do your dishes, clean fish, and do other activities away from the bank and off of boat ramps.
When boating for fishing from a boat, don’t dangle arms and legs over the boat or into the water. If you fall out of a boat, get back in as soon as possible.
Stay back from slide marks. Slide marks are bare smooth spots on banks of rivers, lagoons and wetlands: they are the spots where crocodiles habitually haul themselves on shore.
Don’t provoke or interfere with crocodiles. This includes small hatchlings. While cute by reptilian standards, the little squeaky noise they make can often attract a very large mother, who is very capable of defending her offspring.
Don’t feed crocodiles, either directly, or by leaving fish and food scraps on boat ramps or campsites. Habituating crocodiles to feeding near areas of human activities is a dangerous thing to do.
Camp 2m above the high water mark and 50m from water's edge in crocodile country.
Avoid livestock and wildlife drinking spots. Crocodiles are patient and learned hunters, they know these spots are likely places to find a meal.
Be especially careful during the Sept-Apr. breeding season, crocodiles are often more aggressive, territorial, and hungry during this time of the year.
If camping at a site for a long time don’t form a pattern with your near-the-water activities. If you fish or take water from the river, don’t always do it at the same place at the same time. A crocodile can learn your pattern and arrange to “meet you” after figuring out where and when to next find you near the water’s edge.
when in a boat in croc waters, be very careful, crocs can capsize (tip) boats